Apparatus for pleating paper



Nov. 20, 1956 Q HOCKETT ET AL I 2,771,119

APPARATUS FOR PLEATING PAPER Filed Feb. 11, 1955 5 Sheets-Sheet 1 FIG. I

I CARL s. HOCKE'IT WALTER v. KENNEDY CHESTER A. VANDER mm. A

l BY A I 6W L (WM ATTORNEY Nov. 20, 1956 c. G. HOCKETT ET AL 2,771,119

APPARATUS FOR PLEATING PAPER 5 Sheets-Sheet 2 Filed Feb. 11, 1955 CARL.G. HOCKETT WALTER V.KENNEDY CHESTER A.VANDER PYL,JR'

INVENTORS ATTORNEY Nov. 20, 1956 c HOCKETT ET AL 2,771,119

APPARATUS FOR PLEATING PAPER Filed Feb. 11, 1955 5 Sheets-Sheet 3 E M EA z 64 W 20 I L65? an 6 ..l I 5 1 I I Q E CARL s. HOCKETT WALTER v.KENNEDY H6. 4 CHESTER ANANDER PYL,'JR.

INVENTQRS ATTOR N EY I Nov. 20, 1956 Q HQCKETT ETAL 2,771,119

APPARATUS FOR PLEATING PAPER Filed Feb. 11; 1955 5 Sheets-Sheet 4 k 4 IE 33/ 7% 2? 50 +2/ 25 I 1/ cm. s. HOCKETT' VWALTER v. KENNEDY CHESTER AVANDER PYL,JR

IN V EN TORS L BY ATTORNEY New. 20, 1956 c. G, HOCKETT ET AL. 2,771,119

APPARATUS FOR PLEATING PAPER Filed Feb. 11, 1955 5 Sheets-Sheet 5 CARLG. HOCKETT WALTER V. KENNEDY CHESTER ANANDER PYL,JR.

INVENTORS ATTORNEY United States Patent APPARATUS FOR PLEATING PAPERCarl G. Hockett, Uxbridge, Mass., Walter V. Kennedy, Central Falls, R.1., and Chester A. Vander Pyl, In, North Attleboro, Mass, assignors toFram Corporaiitlm, East Providence, R. 1., a corporation of Rhode s andApplication February 11, 1955, Serial No. 487,642 12 Claims. (Cl.154-30) This invention relates to a rotary pleater for pleating sheetmaterial such as paper, and is capable of pleating such materialaccurately and at high speed.

Sheet material such as cloth and paper has been pleated heretoforebymeans of a reciprocating bar that pushes the material forward against amovable stop to form successive pleats, but the reciprocator pleaterwill not operate at high speed. It has also been proposed heretofore touse cooperating gears provided with inter-acting teeth to bend and pleatpaper and other materials; but this toothed construction tends tostretch and tear paper.

The present invention contemplates a simple apparatus comprisingcooperating feed rolls each having a plurality of longitudinallyextending blades. The rolls serve to feed the material forward and theblades score the advancing material along the desired fold lines. Therolls also cause the material such the paper to bend at the fold lines,as it is pushed away from the rolls, to form the desired pleats. Thisapparatus is capable of forming the pleats accurately and at high speedwithout straining or damaging the paper.

More specifically the primary feature of the present invention residesin a pair of cooperating feed rolls each having several blades extendinglengthwise of the roll and projecting slightly from the roll surface.The blades of one roll are staggered in relation to the blades of theother roll so that the advancing sheet is scored first at one face andthen at the other face by squeezing the sheet between a blade and a rollsurface. Means are provided for retarding the movement of the scoredsheet away from the feed rolls so that it will bend first in onedirection and then the other, as it leaves the rolls, to form theplates. The scored sheet such as paper always bends in a direction tocompress the paper at the scored line, while the opposite face of thepaper that is stretched during the bending action is not weakened by thescoring operation.

The feed rolls above mentioned as provided with the longitudinallyextending scoring blades may be variously constructed. For example,these rolls may each have a smooth outer surface that backs up the papersheet While it is being scored by a blade, or the backing rolls may beprovided with slight depressions in which the paper is pressed by thescoring blades. Furthermore, theserolls may, if desired, be providedwith annular ribs and grooves for forming shallow ribs lengthwise of thepaper passing between the rolls.

The rotary pleater of the present invention was designed primarily topleat porous paper used to filter gases such as air, and liquids such asengine lubricating'oils. Such filter paper, in order to perform well,needs to be an uncalendered paper, as calendered rolls tend to gloss thesurface of a sheet and close its pores. Furthermore, such filter papershould be sufficiently stiif when used in an air or oil filter towithstand the up-stream fluid pressure without collapsing in use. Also,such filter paper should have good filtering properties so that it willremove all dirt particles larger than a predetermined size and will ICCfunction for a long time before it becomes so clogged with dirt that itneeds to be replaced. As a result of these requirements, such filterpaper is very difierent from relatively firm, strong, tough calenderedpaper, and the present rotary pleater was carefully designed to pleatuniformly, comparatively tender felt paper without crack ing the paperor injuring its surface.

The present pleater is a precision machine in that it will operate toform pleats that are highly uniform as to height and fold, and will runat very high speed. For example, the reciprocating pleater abovementioned, when used to form paper pleats about one inch high, will notproduce more than about pleats per minute,.whereas the present rotarypleater will produce the same size paper pleats at a speed of over 6000per minute.

The above and other features of the present invention will be furtherunderstood from the following description when read in connection withthe accompanying drawings; wherein,

Fig. l is a side elevation of a rotary pleating machine constructed inaccordance with the present invention.

Fig. 2 is a top plan view of Fig. 1.

Fig. 3 is a sectional view taken on the line 3 '3 of Fig. 1.

Fig. 4 is a sectional view taken on the line 44 of Fig. 1.

Fig. 5 is a sectional view taken on the line 5-5 of Fig. 2.

Fig. 6 is a side view of a portion of the machine illustrated in Fig. 1showing the opposite side from that of Fig. 1.

' Fig 7 is a vertical sectional view through part of the cooperatingfeeding and scoring rolls and shows how the paper is scored.

Fig. 8 is a perspective view showing the paper after it has beenpleated.

' Fig. 9 is a modification showing the feed rolls as having shallowdepressions that cooperate with the scoring blades.

Fig. 10 is a modification showing the feeding and scoring rolls ashaving annular grooves and ribs.

Fig. 11 is a longitudinal sectional view through partof the rolls ofFig. 10.

Fig. 12 shows the paper having the longitudinal ribs formed by the rollsof Fig. 10; and

Fig. 13 is a modification showing in end view the feeding and scoringrolls with one yieldingly mounted. with respect to the other.

Referring to the embodiment of the invention shown in Figs. 1 to 8, theentire device may be mounted on a table or other supporting means whichwill support the machine at a desired distance from the floor.Themachine is shown as having a base portion formed of an angle beam 10which has the downwardly extending side walls 11. To this beam 10 aresecured near one end thereof the uprights 12 and 13 adapted to supportthe feed rolls to be described. The upright 12 is shown as considerablywider than the upright 13, and these uprights are welded or otherwisesecured to a base plate 14 that is rigidly fastened to the beam 10. Eachupright ll and 13 is provided with a bearing 15 in which the shaft 16for a lower roll 17 rotates. The shaft 16 is power driven and is rigidlysecured to the roll 17 mounted tend longitudinally thereof and theyproject a'slight distance from the curved outer surface of the roll, sothat when a sheet of paper P is advanced between these rolls, it will beperiodically scored, as best shown in Fig. 7. It should be pointed out-that the blades 23 of the upper roll are staggered with respect to theblades 23 of the lower roll so that the paper passing between the rolls17 and 22 will be scored first at one face and then at the other, aswill be apparent from Figs. and 7. The blades 23 do not cut the paperbut compress the same at the fold lines as shown and bend the paperinitially in the direction in which it is to be further bent to form thedesired pleat. It is desired to emphasize the fact that for best resultsthe paper should be compressed at the exact line of fold.

The distance between the blades 23 mounted in each roll, in theconstruction shown, is equal to twice the height of a paper pleat, andthe blades in the lower roll 17, as shown, are likewise spaced apart adistance equal to twice the height of a paper pleat. That. is, the pitchof these blades, or are, from the center line of one blade to the centerline of the next blade at the contact edge is equal to twice the heightof a pleat. Therefore, since the paper P passing between these rolls isscored first at one face and then at the other face, it will be scoredat its opposite faces at just the desired distance apart to form pleatsof a pre-determined height. The diameter of each roll 17 and 22preferably is not more than several times the height of a pleat, becauseif very large rolls are used relative to the height of the pleat, thelarge radius of these rolls near the discharge nip will interfere with'the bending of the paper laterally from a central hori zontal plane toform the pleats. This will be understood from an examination of Fig. 5.It is desired to point out that the pressure of a blade 23 against thepaper causes it to bend in the proper direction to form the next fold,as will be apparent from Figs. 5 and 7.

The feed rolls 17 and 22 are power driven and serve to draw a long stripof paper P forward from asource of supply such as a wound roll, notshown; and as the paper passes between these feed rolls, it is scoredfirst at one face and then at the other, asabove stated. As the scoredpaper is pushed away from the nip of these rolls by their rotation, itis easy to cause the paper to form the desired pleats by simplyretarding the travel 'ofthe scored paper away from such rolls, so thatthe action of the rolls pushing the paper away from the nip thereof willcause the scored paper to bend alternately up and down, as shown in Fig.5, to form the desired folds or pleats F.

It is important to provide guide means which will facilitate forming thepleats just mentioned and will also serve to guide these pleats awayfrom the rolls along a pre-determined path. Such guide means in theconvstruction shown comprises two laterally spaced lower bars 24 alongwhich the pleats slide. Two laterally spaced upper bars 25 are alsoshown. These bars, in the construction shown, are supported the desireddistance above the angle beam base by the L-shaped brackets 26 which arebest shown in Fig.4. These L? shaped brackets support a U-shaped brackethaving the horizontal bar 27 and the upright legs 28. The L-shapedbrackets 26 are bolted to the beam 10 and the U-shaped bracket issecured by the bolts 29 to the upstanding legs of the brackets 26. Thelower guide bars 24 are supported by the horizontal bars 27, and theupper bars'25 are secured to and supported by the transversely extendingbridge bar 30 which is secured to the upper ends .of the legs 28. Thebars 24 and 25, as will be apparent from Figs. 1 and 2, are supported bytwo sets of brackets 'such as just described and shown in Fig. 4. Thesebrackets serve also to support horizontally extending sidebars 31 whichhelp to define the path along which the pleats F travel as they arepushed away from the nip of ,the rotating rolls. The bars 24 and may beadjusted to receive pleats of difierent height.

In order to cause the scored paper to fold back and forth at the scoredlines to produce the desired pleats, it is necessary to retard thetravel of these pleats away from the rolls 17 and 22. When the machineis first started up and is rotating slowly, the operator may use hishand to retard the travel of these pleats away from the rolls along thelower guide bars 24; but as soon as a substantial number of pleats havebeen formed, the desired resistance to the travel of these pleats alongthe guides 24 away from the feed rolls is secured, in the constructionshown, by providing two or more weighted retarding plates, such asindicated by 32, and each of which may comprise a flat metal plate whichis curved upwardly at its forward end as indicated by 33. This forwardend is welded or otherwise secured to a pivot pin 33, the opposite endsof which are journaled in the supports 34 that are rigidly secured tothe upper face of the bridge member 30. The arrangement is such thatthese retarding plates 32 may swing up and down to rest yieldingly uponthe upper folded edge of the advanced pleats F. The downward movement ofthese plates is preferably arrested by the stop rods 32. In order tovary the pressure each of these pivoted plates 32 will exert upon thetops of the pleats, each plate 32 preferably has extending upwardlytherefrom a post 35 on which any desired number of disc-shaped weights36 may be placed to rest upon such plate. Each weight 36 has a centralhole adapted to receive the guide post 35. In this way the load uponeach plate 32 may be varied as desired by varying the number of weights36 placed thereon.

Each lower guide bar 24 is provided at its forward end with a blade ,37which projects into an annular recess 38 formed about the roll 17, andeach upper bar 25 is provided with a similar blade 39 that projectsintoan annular recess 40 that encircles the upper roll 22. The purpose ofthese protruding blades 37, 39 is to prevent the advancing paper fromclinging to the surface of a roll and following around a roll. The upperbars 25 as shown do not touch the pleats F, and their main function isto support the pivoted plates 32. The receiving end of the machine shownis preferably provided with a guiding apron 41 having the upstandingsides 42 and transverse bars 43. This construction is such as to guidethe paper strip P to be pleated from a suitable source of supply.

.It is desirable .to make provision for adjusting one feed roll towardsand from the other, to vary the feeding pressure exerted upon-the sheetof paper P passing between the rolls and to accommodate paper ofdifferent thickness. This is accomplished, as shown in Fig. 1, bymounting the shaft 21 .of the upper roll in the sliding blocks 19 abovedescribed. These blocks at each side of the machine are continuouslyurged upwardly by a coiled spring 44, and upward movement of'theseblocks 19 under th pressure of the springs 44 is limited by theadjustable screws .45, having a knurled head, and the lower end of thesescrews engages the sliding blocks 19. Each screw is provided with a locknut 46.

It is important to positively drive both rolls. In the constructionshown the'shaft 16 of the lower roll is provided with a V-shaped drivingpulley 47 that has the driving belt 48. The shaft 16 has rigidly securedthereto a driving gear 49 which, through a train of gears, positivelydrives the upper feed roll 22 and also permits vertical adjustment ofthis roll. To this end, the gear 49 drives a laterally disposed gear 50which is rotatably mounted on the upright 12 by. a stub shaft 51. Thisgear 50 meshes with an :upper gear 52 which is rotatably mounted on anadjustable stub shaft 53 supported by the upright v12. The gearf52 inturn meshes with and drives a gear :54 which is mounted upon the ,upperroll shaft 21. Since, as above stated, the present machine is aprecision machine that operates to form pleats that .arevhighly uniformas to height it is found desirable to :provide means whereby the g ar:54 may be angularly adjusted through a small angle with respect to theshaft 21 it drives. This is important because as the space between theupper and lower feed rolls is varied, the angular position of the upperblade 23 with respect to a pair of lower blades 23 will be shiftedslightly, with the result that successive pleats will not be ofidentical height. This can be corrected by adjusting the gear 54 veryslightly in an angular direction with respect to its shaft 21, and thelocking bolts 55 are provided to permit this angular adjustment of thegear 54. In the construction shown, the lower drive gear 49 is enclosedin the protecting housing 56. As the accumulated pleats F travellengthwise of the guide bars 24, they finally reach the discharge apron57. It may be desirable to employ herringbone gears as the gears 49, 50,52 and 54 to reduce back-lash between the rolls 17 and 22.

The pleating machine of the present .invention may be employed to pleatpaper or other sheet material, but was designed primarily to pleat athigh speed porous filter paper used to form filter elements adapted tofilter liquids, such as oil, or gases such as air. The paper P is,therefore, a selectedpaper having the desired porosity and is preferablytreated with a resin such as phenol formaldehyde that serves to toughenthe paper and impart stiffness thereto without seriously reducing itsporosity. In order that the fluid to be filtered may enter between thefilter pleats when they are pressed close together, it has been foundheretofore desirable to provide such paper with slight ribs and groovesextending longitudinally of the paper strip, as shown in Fig. 10, and inwhich the filter fluid may travel towards the folds of the pleatedpaper.

It has, therefore, been the practice heretofore to pass the long stripof filter paper between grooving rolls which will provide the same withshallow longitudinal grooves as the paper approaches the pleatingmachine. It is found, however, that the rolls used to provide theselongitudinal grooves cause the paper to spread laterally some what, thuschanging its width. To overcome this difficulty, it is desirable toprovide cutters which will trim the side edges of the sheet so that itwill have just the desired width as it approaches the pleating mechanismof the present invention. The longitudinal grooving rolls just mentionedshould be driven in accurate timed relation with the feed rolls 17 and22 so that both sets of rolls will advance the paper at the same speed.The cutters for trimming the sides of the sheet may be rotating cuttersdriven at high speed; they may be driven from the shaft 16 by pulley 58and belt 59.

The paper being pleated preferably contains, as above stated, a resinousmaterial such as phenol formaldehyde and preferably is in a slightlymoist condition when pleated, which facilitates the bending of the paperto form the pleats. The pleated paper upon leaving the discharge apron57 preferably goes into a curing oven, not shown, that serves toheat-cure and set the resin of the paper. Such curing oven may havechains or aprons for advancing the pleats through the oven at apredetermined speed with respect to the speed at which the pleats areformed by the apparatus of the present invention. The shaft 16 is,therefore, shown as provided with a third pulley 61} which may beemployed to drive the chains just mentioned of the curing oven at adesired speed with respect to the speed of the pleating machine of thepresent invention.

' While in the apparatus shown and described the pleater serves toproduce at high speed pleats that are highly uniform as to height, theapparatus contemplated by the present invention can be used to producepleated paper having alternately high and low pleats, since all that isnecessary to accomplish this is to change the position and number ofscoring blades 23 provided in one roll with respect to the scoringblades 23 of the other roll. To change from pleats of one'height topleats of a different height, the rolls 17 and 22 should be replaced byother rolls having the blades 23 spaced apart a distance equal to twicethe height of a pleat.

It will be seen from the foregoing that the advancing sheet of paper Pis scored transversely by the pressure exerted by the blades 23 whilethe paper rests against the backing roll 17 or 22, and that the paper isscored in the direction in which the paper is to be bent, so that thescore is always at the inside of the bend rather than at the outerradius of the bend. This is desirable because as a result of thisconstruction the paper is not weakened at the curved outer surface ofthe bend where the strain is most severe.

While the pleating rolls above described do an excellent job in pleatingcomparatively soft paper which has not been calendered, its scoringpressure on relatively firm paper may .injure such paper. Therefore, inworking with a firm compact paper, it may be desirable to use themodified construction shown in Fig. 9 and wherein the scoring bladespress the paper into shallow recesses.

Now referring to Fig. 9, the paper P is shown as'having the slight ribsR extending longitudinally thereof. This paper is shown as being actedupon by the cooperating feeding and scoring rolls 61 and 62. Each ofthese rolls has the longitudinally extending scoring blades 63, andthese rolls operate the same as rolls 17 and 22 to score the paper,except that the rolls 61 and 62 are provided with the shallowlongitudinally extending recesses 64 positioned to cooperate with theblade 63 as shown. The scoring blades 63 act to deflect the paper P intothe recesses 64 as shown in Fig. 9 to form the fold lines of the pleats,without the necessity of forcing the blades deep into the paperstructure. By using the construction of Fig. 9 a firm paper can bepleated in accordance with the present invention without injuring thepaper sheet. If desired, instead of providing each roll with therecesses 64, the rolls 61 and 62 may be provided with inserted rubberblocks, not shown, positioned to yieldingly receive the pressure of ablade 63 against a roll.

The modified construction shown in Fig. 10 comprises cooperating feedrolls 65 and 66 having extending longitudinally thereof the scoringblades 67. These rolls 65 and 66 operate the same as rolls 17 and 22except the rolls of Fig. 10 are provided with the annular ribs 68 andgrooves 69, as shown in Fig. 11, and which act to impart to the sheet ofpaper P" the longitudinally extending ribs 70 (see Fig. 12). It will beseen that the rolls of Fig. 10 perform the double function of providingthe paper with longitudinal ribs and with transverse pleats as shown.

The apparatus of the present invention was, as above stated, designedprimarily to pleat a porous uncalendered paper. Such paper is likely,in' a single sheet, to vary considerably in thickness throughout itslength, so that if a thick section of a running sheet should passbetween rolls 17 and 22, the blades 23 would score this portion of thepaper deeper than desired. To avoid this ditficulty it may be desirableto employ the modified construction of Fig. 13 and wherein spring meansare provided to permit one roll to move away from the other when thepressure between them becomes excessive. The construction shown in Fig.13 has the feed rolls 71 and 72 that may be identical in constructionand operation to rolls 17 and 22, except that roll 72 can move upwardlyslightly when the pressure on the paper becomes excessive. In this vieware shown the uprights 73 which are provided at each end of the rolls.These uprights at each end of the rolls have a fixed bearing block 74and sliding upper bearing block 75. The distance between these blockscan be varied by moving the sliding wedge 76 between them in thedirection of its length. Each sliding upper block is continuously urgeddownward by a coiled spring 77 and the pressure exerted by each springmay be varied by adjusting the bolt 78 that presses downward on suchspring. The springs 77 will serve not only to relieve excessive pressureupon the paper passing therebetween, but may be employed also tomaintain sufiicient pressure between the rolls to insure a positive feedof the paper at all times. To accomplish this, the wedges 76 should bebacked off from between the blocks enough to permit the rolls to gripfirmly between them the thinnest paper passing therebetween.

The apparatus of the present invention, while very simple inconstruction, produces highly uniform paper pleats at high speed.Furthermore, the mechanism of the present invention will pleatuncalendered filter paper having felt-like properties, withoutstretching the paper or scuffing its surface, or otherwise changing theporosity of this filter web.

Having thus described our invention, what we claim and desire to protectby Letters Patent is the following:

1. Apparatus for pleating an advancing sheet of filter paper, comprisinga pair of feed rolls each having a sheet engaging outer surface, scoringblades extending longitudinally of the rolls and protruding slightlyfrom the roll surface in staggered relation one to the other so thatwhen the rolls are rotated they continuously engage and advance thesheet and score it at first one face and then the other, a guide way forthe pleated sheet delivered by the rolls, and means for retarding theadvancing movement of the pleats along the guide way to thereby causethe paper to bend back and forth near the rolls at the score lines.

2. Apparatus as in claim 1 wherein the sheet material is compressed bythe blade to reduce its thickness along the score lines.

3. Apparatus as in claim 1 wherein the sheet material is scored bypressing it between a scoring blade of one roll and a smooth backingsurface of the other roll.

4. Apparatus as in claim 1 wherein the nip of the two rolls serves topull the sheet forward to the rolls.

5. Apparatus as in claim 1 wherein loaded weights constitute the meansfor retarding the advancing movement of the pleats along the guide way.

6. Apparatus as in claim 1 wherein the sheet is folded in a direction tocompress the sheet material along the scored line.

7. Apparatus for pleating an advancing sheet of uncalendered filterpaper, comprising a pair of feed rolls each having a paper grippingsurface and each having several scoring blades extending lengthwise ofthe roll and protruding slightly from the roll surface, the blades ofone roll being staggered relatively to the blades of the other roll sothat when the rolls are rotated they will continuously grip and advancethe paper and score it at first one face and then the other, and meansfor retarding the movement of the scored paper away from the rolls so asto cause it to bend back and forth along the scored lines and formpleats.

8. Apparatus for pleating an advancing sheet of uncalendered paper,comprising a pair of feed rolls geared together and each having scoringblades extending lengthwise thereof and protruding slightly from theroll surface in staggered relation one to the other so that the rotatingrolls will continuously grip and advance the sheet and score it at firstone face and then the other, means for retarding the movement of thescored sheet away from the rolls so as to cause it to bend back andforth along the scored lines to form pleats, and one of said rollshaving a gear that can be adjusted angularly relatively to such roll soas to vary the angular position of the blades of one roll to the bladesof the other roll.

9. Apparatus for pleating an advancing sheet of run calendered paper,comprising a. pair of feed rolls having cooperating paper advancingsurfaces, each roll having several scoring blades extending lengthwisethereof and protruding slightly from said surface and also havingshallow recesses extending lengthwise of the roll, the blades of oneroll being staggered relatively to the blades of the other roll tocooperate with said recess to press the paper therein and form scorelines on first one face of the paper and then the other, and means forrotating the rolls so that they will advance the scored paper againstretarding means to cause it to bend back and forth along the scoredlines to form pleats.

10. Apparatus for pleating an advancing sheet of uncalendered paper,comprising a pair of feed rolls having cooperating paper advancingsurfaces, each roll having several scoring blades extending lengthwisethereof and protruding slightly from said surface, the blades of oneroll being staggered relatively to the blades of the other roll so thatwhen the rolls are rotated they will score the paper at first one faceand then the other, said rolls having annular grooves and recesses toform ribs lengthwise of the paper, and means for retarding the travel ofthe scored paper away from the rolls so as to cause it to bend back andforth along the scored lines to form pleats.

11. Apparatus for pleating an advancing sheet of uncalendered paper,comprising a pair of feed rolls having cooperating paper advancingsurfaces, each roll having several scoring blades extending lengthwisethereof and protruding slightly from said surface, the blades of oneroll being staggered relatively to the blades of the other roll so thatwhen the rolls are rotated they will score the paper at first one faceand then the other, means for yieldingly pressing one roll towards theother so that the disstance between the rolls can increase if thepressure hecomes abnormally high, and means for retarding the travel ofthe scored paper away from the rolls so as to cause it to bend back andforth along the scored lines to form pleats.

12. Apparatus for pleating an advancing sheet of filter paper so as toproduce pleats that are highly uniform as to height and fold formation;comprising a pair of smooth surfaced cylindrical feed rolls each havingscoring blades extending lengthwise of the roll and arranged to protrudefrom the roll a distance substantially less than the thick ness of thepaper to be pleated, said rolls being positioned so that the blades ofone are staggered relatively to the blades of the other and each bladeserves to press the paper against the other roll to compress the paperalong the line of fold, means for rotating the rolls so that the paperis continuously gripped and advanced by the nip of the rolls along aguide way, and means for retarding the movement of the pleats along theguide way to thereby cause the paper to bend back and forth at the scorelines and form successive pleats.

References Cited in the file of this patent UNITED STATES PATENTS2,141,235 Angeletti Dec. 27, 1938 2,668,573 Larsson Feb. 9, 1954 FOREIGNPATENTS 635,694 Great Britain Apr. 12, 1950 868,211 France Sept. 22,1941 943,803 France Oct. 11, 1948 627,355 Germany Mar. 13, 1936 637,654Germany Nov. 2, 1936

